Fluid collection sets, intravenous infusion sets and catheters are employed respectively for collecting bodily fluids from a patient, for infusing liquids into a patient. Fluid collection sets and intravenous infusion sets include a length of flexible plastic tubing with a proximal end connected to a plastic fitting and a distal end connected to a needle assembly. The needle assembly includes a hub and needle cannula. A pair of flexible plastic wings is mounted to or near the hub. The wings can be folded into face-to-face engagement with one another, and hence define a convenient handle for gripping and manipulating the needle cannula. The wings also can be rotated away from one another and can be taped into face-to-face contact with the skin of the patient. A catheter typically is used with an elongate piercing element for introducing the catheter into a patent.
Accidental sticks with a needle cannula can be painful and can transmit disease. As a result, most needle assemblies and other sharp medical implements are employed with rigid means for enclosing at least the sharp tip both prior to use and after use. Protection prior to use typically is achieved by a rigid plastic tube that has a proximal end frictionally mounted to or near the hub and a distal end that extends beyond the distal end of the piercing element. The plastic tube is removed and discarded immediately prior to use of the piercing element. Protection after use typically is achieved by a tubular shield that can be telescoped relative to both the hub and piercing element from a proximal position where the piercing element is exposed to a distal position where the piercing element is safely within the tubular shield. Shields of this type typically include means for releasably holding the shield in its proximal position and for holding the shield more securely in its distal position. Some devices include a spring for generating relative movement between the shield and the piercing element. In some instances, the shield is moved distally over the piercing element. In other instances, the piercing element is withdrawn proximally into the shield.
A small volume of blood or other bodily fluid may remain in or on a piercing element after the piercing element has been withdrawn from the patient. This residual fluid may splatter as the piercing element is retracted rearwardly into a shield. The probability of such splatter from a needle is dependent upon several factors, including the gauge of the needle, the acceleration of the needle in the proximal direction, the presence of any transverse movement of the needle during its rearward acceleration, the extent of capillary adhesion of the residual fluid on portions of the cannula that define the lumen and other factors. Splatter of bodily fluid can transmit disease.
Health care workers are required to use many different medical devices, and often use medical devices from several different manufacturers. The configuration and operation of the shields on the above-described medical devices vary widely from one manufacturer to another. A lack of familiarity with the specified operation of a shield for a particular medical device can lead to improper shielding and hence creates the potential for an accidental stick with a used needle cannula.
The ease of shielding and the effectiveness of the shielding also vary from one type of medical device to another. Devices that are mechanically simple may provide less effective shielding. More secure shielding may require more complex manipulation of the device by the health care worker. In view of the above, a demand exists for a medical device that provides secure shielding and an easy operation.